Keep state with env

demo/moulinrouge/tests.py

@@ -635,4 +635,11 @@ def get_test_routes(app):
         graph.add('inverse', [1, 2, 3, 12, 24, 36])
         return graph.render_response()
 
+    @app.route('/test/only_zeroes')
+    def test_only_zeroes():
+        line = Line()
+        line.add('zeroes', [])
+        line.add('zeroes 2', [0])
+        return line.render_response()
+
     return list(sorted(filter(lambda x: x.startswith('test'), locals())))

pygal/graph/base.py

@@ -35,6 +35,7 @@ from pygal.adapters import (
 from functools import reduce
 from uuid import uuid4
 import io
+import os
 
 
 class BaseGraph(object):
@@ -216,6 +217,9 @@ class BaseGraph(object):
         self.svg.pre_render()
 
     def teardown(self):
+        if os.getenv('PYGAL_KEEP_STATE'):
+            return
+
         del self.state
         self.state = None